delphi idhttp post 普通提交亂碼處理

var
  IdHTTP1:TIdHTTP;
  postStream : TStringStream;
  Wstr:WideString;

res:WideString;
begin

 IdHTTP1 := TidHTTp.create(nil);
     try
        Wstr:= 'aaccount=' + aaccount;
        Wstr:=Wstr+'&'+'passwd=' +passwd;
  postStream:=TStringStream.Create(ansitoUTF8(Wstr));
        IdHTTP1.Request.ContentType := 'application/x-www-form-urlencoded';

      try
         res:=Utf8ToAnsi(IdHTTP1.Post(infoURl,postStream));
      except
       on E:Exception do
       begin
          MsgBox('錯誤信息:' +e.message);
       end;
      end;
        vJson := SO(res);

end;

　　

用stringlistPOST提交時會亂碼，改用該方法后解決。